The concepts and definitions of pollution were provided in Chapter 8 and the differences between pollution and contamination were also explained in Section 8.2.2 as necessary parts of the topic on the chemical degradation of soils. This chapter will specifically address pollution of soils and their causes in detail, which for several reasons were felt not appropriate for discussion in Chapter 8. Though the topic of pollution would have been considered by some closely related to the degradation of soils (but not necessarily so by others), a detailed discussion on soil pollution would have made Chapter 8 excessively long and may interrupt the sequence of reading apprehension. Soil pollution is generally caused by the introduction of large amounts of both harmless and harmful materials, usually in the form of waste, into the soils, which in turn may spread to become water and air pollution. The common pollutants are organic and inorganic waste from large livestock operations, municipal landfills, food processing plants, oil refineries, industry and many more. In the modern society of today, pollution can also be caused by sophisticated, high-tech operations. For example, noise pollution, due to excessive noise from tractor trailer trucks and cars on interstate highways and from flights of supersonic aircrafts, is a health hazard. Excessively loud music
from amplifiers in cars and houses is also a big, deafening nuisance, resulting in possible hearing loss and high blood pressure. Automobiles and tractor trailer trucks are allegedly the sources of ninety percent of unwanted noises. Thermal pollution, by discharge of water coolants from power plants and nuclear facilities, causes rapid temperature changes in rivers and lakes, affecting aquatic life. This is another type of pollution created by modern technology. Light pollution, due to over-illumination and visual pollution because of billboards on highways and overhead high voltage power lines, is an additional new type of pollution of our modern society. It is also considered a major source of headaches. With the development of biotechnology with its gene transfer, genetic pollution has been added to the list. For the purpose of protecting public health and the environment, international treaties were established by the United Nations, and two of the most important ones are the so-called Montreal Protocol of 1987 on controlling mainly ozone depletion and the Kyoto Protocol of 1997 on reducing greenhouse gases. The latter was replaced in 2007 by the treaty of the Bali conference. All these will be addressed in the appropriate sections later in this chapter. In the following sections, the emphasis will be on soil, water and air pollution due to careless disposal of agricultural, household, municipal and industrial waste.